//#define _CRT_SECURE_NO_WARNINGS 1
//#include<iostream>
//using namespace std;
////
////int& func()
////{
////	int a = 0;
////	return a;
////}
////
////int main()
////{
////	int& ret = func();
////
////	return 0;
////}
//
//#include <iostream>
//#include <sstream>
//#include <string>
//#include <vector>
//using namespace std;
//// 0123456789ABCDEF
//const string map = "0123456789ABCDEF";
//
//string toHex(int num)
//{
//    string ret;
//    while (num > 0)
//    {
//        ret += map[num % 16];
//        num /= 16;
//    }
//    while (ret.size() < 2) ret += '0';
//    reverse(ret.begin(), ret.end());
//
//    return ret;
//}
//
//string ipv4ToHex(string ip)
//{
//    vector<int> parts;
//    stringstream ss(ip);
//    string e, ret;
//    
//    while (getline(ss, e, '.')) parts.push_back(stoi(e));
//    for (int e : parts) ret += toHex(e);
//    
//    return ret;
//}
//
//int main() {
//    string ip = "192.168.1.1";
//    string hex = ipv4ToHex(ip);
//    cout << "IPv4: " << ip << endl;
//    cout << "Hex: 0x" << hex << endl;
//    return 0;
//}